Thrust Vector/Center of Mass issues

[Nertea]

So I have a large number of engines that have slightly asymmetric thrusts (a rotation is created at high thrust). This is pretty vexing, and I'm not exactly sure why it occurs. So I thought I'd ask for help.

1) The part's root (with the PartTools component) is centred directly on the Unity origin and contains the engine mesh, colliders and the thrust transform. As I understand it this defines the CofM

2) The thrust transform is directly below the origin, pointing exactly straight down (typed the rotation in numerically) and aligned exactly with the origin in all but one direction (again, numerically entered).

This seemed correct. Am I doing this right? Because some of my engines have an offset thrust and some don't. Anything else I should be taking into account? I can also add pictures if it would help.

- edit: This is being tested with infinite fuel + a single MK1 command pod. So other parts shouldn't interfere.

[Nertea]

For the reference of anyone having these problems, I've largely fixed this by doing the following:

• Ensure that colliders are perfectly symmetrical and zeroed
  
• Zero all transform axes AND rotations
  
• Restart from 3D program export if needed
  

I went through these for everything and it fixed all them, seems like.

[Dispatcher]

Thanks for the info. Glad it worked!